At home router problem

I am hoping someone can shed some light on this for me...
At home we have 4 PCs - 2 desk tops (Vista OS) 2 laptops (XP OS) all using the same wireless router.
One laptop can still 'see' the router, but can not access the internet when the signal strength is Excellent. One desk top is hard wired to the router so it is fine; the other uses a wireless connection and it seems to not be working or even 'seeing' the router. The other laptop nothing...no connection at all.
Any ideas as to what could be the problem. We have called hp and gone through all their ideas and still nothing.

Hi,
it seems the error u r not accessing the internet .. on laptop is just make your laptop to take ip dynamically (if there any static ip remove that) the next thing is check is there any proxy ? make it sure.
the second lap top check the wireless switch is on ?
and check on the 3Com the wireless is enabled or not ?
i hope it could resolve your issues...

hi,
Let me know the Brand name and Model # of the wireless router
Check the IP address and default gateway on the wired computer
(Start-->Control panel-->(network and internet) or Network and Sharing center--> on your left... click on manage network connections--> right click on Local area connection--> status--> details--> IPV4 IP address and default gateway)
if there is any wireless computer connected to the wireless network let me know the IP address and default gateway on that too

By "see" do you mean that when you search for wireless networks, it doesn't show up? If you are "seeing" other people's wireless when you search,but not your, the problem is with the router.
Make things as simple as possible on the wireless. As a test, go to the router settings, make sure it is set to broadcast SSID and has no encryption. Try making connections again and see if it works. When you are done, make sure you turn encryption back on so nobody hijacks your network.